1. Field of the Invention
The present invention relates generally to telecommunications systems and methods for delivering Short Message Service (SMS) messages, and specifically to allowing a SMS message to be received by a specified group of subscribers.
2. Background and Objects of the Present Invention
Cellular telecommunications is one of the fastest growing and most demanding telecommunications applications ever. Today it represents a large and continuously increasing percentage of all new telephone subscriptions around the world. A standardization group, European Telecommunications Standards Institute (ETSI), was established in 1982 to formulate the specifications for the Global System for Mobile Communication (GSM) digital mobile cellular radio system in use today, and described in more detail herein.
With reference now to FIG. 1 of the drawings, there is illustrated a GSM Public Land Mobile Network (PLMN), such as cellular network 10, which in turn is composed of a plurality of areas 12, each with a Mobile Services Center (MSC) 14 and an integrated Visitor Location Register (VLR) 16 therein. The MSC/VLR areas 12, in turn, include a plurality of Location Areas (LA) 18, which are defined as that part of a given MSC/VLR area 12 in which a mobile station (MS) 20 may move freely without having to send update location information to the MSC/VLR area 12 that controls the LA 18. Each Location Area 12 is divided into a number of cells 22.
Mobile Station (MS) 20 is the physical equipment, e.g., a car phone or other portable phone, used by mobile subscribers to communicate with the cellular network 10, each other, and users outside the subscribed network, both wireline and wireless. The MS 20 may also include a Subscriber Identity Module (SIM) card 13, or other memory, which provides storage of subscriber related information, such as a subscriber authentication key, temporary network data, and service related data (e.g. language preference).
The MSC 14 is in communication with at least one Base Station Controller (BSC) 23, which, in turn, is in contact with at least one Base Transceiver Station (BTS) 24. The BTS is the physical equipment, illustrated for simplicity as a radio tower, that provides radio coverage to the geographical part of the cell 22 for which it is responsible. It should be understood that the BSC 23 may be connected to several base transceiver stations 24, and may be implemented as a stand-alone node or integrated with the MSC 14. In either event, the BSC 23 and BTS 24 components, as a whole, are generally referred to as a Base Station System (BSS) 25.
With further reference to FIG. 1, the PLMN Service Area or cellular network 10 includes a Home Location Register (HLR) 26, which is a database maintaining all subscriber information, e.g., user profiles, current location information, International Mobile Subscriber Identity (IMSI) numbers, and other administrative information. The HLR 26 may be co-located with a given MSC 14, integrated with the MSC 14, or alternatively can service multiple MSCs 14, the latter of which is illustrated in FIG. 1.
The VLR 16 is a database containing information about all of the Mobile Stations 20 currently located within the MSC/VLR area 12. If a MS 20 roams into a new MSC/VLR area 12, the VLR 16 connected to that MSC 14 will request data about that Mobile Station 20 from the HLR database 26 (simultaneously informing the HLR 26 about the current location of the MS 20). Accordingly, if the user of the MS 20 then wants to make a call, the local VLR 16 will have the requisite identification information without having to reinterrogate the HLR 26. In the aforedescribed manner, the VILR and HLR databases 16 and 26, respectively, contain various subscriber information associated with a given MS 20.
With reference now to FIG. 2 of the drawings, text messages, containing up to 160 alpha numerical characters, can be sent to and from MSs 200, using the Short Message Service (SMS) 210. SMS 210 utilizes a Service Center 220, which stores and forwards short messages to MSs 200. A SMS 210 message can be sent from the Service Center 220 to the MS 200 or from the MS 200 to the Service Center 220.
The mobile terminated SMS 210 transfers a short message from the Service Center 220 to the MS 200. In addition, information about the delivery of the short message is returned to the Service Center 220. This information is either a delivery report, which confirms the delivery of the message to a recipient, or a failure report, which informs the originator that the short message was not delivered and the reason why. If the information is a failure report, the originator has the ability to order retransmission later.
A mobile terminated SMS message 210 typically originates by a user 240 sending a message to the Service Center 220, which then forwards the message to the SMS Gateway Mobile Switching Center (SMS-GMSC) 250. Thereafter, the SMS-GMSC 250 interrogates the HLR 260 for routing information pertaining to the designated MS 200. The HLR 260 returns this routing information to the SMS-GMSC 250, which can then route the message to the MSC/VLR 270 serving the location area (LA) 205 that the MS 200 is in. If the MS 200 is in IDLE mode (not in use), the MS 200 is paged, and a connection is set up between the MS 200 and the network 270, as in the normal call setup case. The MSC/VLR 270 then delivers the SMS message 210 to the MS 200. SMS messages 210 are preferably transmitted on the allocated signaling channel. However, if the MS 200 is in busy mode (in use), the SMS message 210 will be transmitted on the Slow Associated Control Channel (SACCH). In that case, no paging, call setup, or authentication need to be performed.
After the MSC/VLR 270 sends the SMS message 210 to the MS, a delivery report is sent from the serving MSC/VLR 270 to the Service Center 220. If delivery of the SMS message 210 was not successful, the HLR 260 is informed, and a failure report is sent to the Service Center 220. In addition, if the delivery was unsuccessful, a Messages Waiting service 215 within the Service Center 220 can optionally provide the HLR 260 and the serving MSC/VLR 270 with the information that there is a message in the originating Service Center 220 waiting to be delivered to the MS 200. Once the MS 200 becomes available for receipt of the SMS message 210, the HLR 260 informs the Service Center 220 and the SMS message 210 is sent again. The mobile terminated SMS message 210 can be input to the Service Center 220 by a variety of sources, e.g., speech, telex or facsimile.
A mobile originated SMS message can also be submitted by the MS 200 to the Service Center 220. The MS 200 first establishes a connection to the network (serving MSC/VLR 270), as in the case of a normal call setup. However, it should be noted that if the MS is in busy mode, a connection already exists. Once a connection is made with the serving MSC/VLR 270 and the authentication of MS 200 is confirmed, the MS 200 can send the SMS message to the Service Center 220 via the serving MSC/VLR 270. The Service Center 220 in turn forwards the SMS message 210 to its destination, which could be another MS 240 or a user in the fixed network (not shown), the former of which is illustrated in FIG. 2. Once the SMS message 210 is delivered to the end user 240, either a delivery report or a failure report is sent to the Service center 220.
The SMS messages 210 can currently be sent point-to point, e.g., from one subscriber to another subscriber, or can be broadcast to all subscribers in a cell 208. This latter method of delivery does not differentiate between particular groups of subscribers, as all subscribers within the cell 208 are treated as one group. Thus, many subscribers do not use SMS 210 to send messages to a particular group of subscribers, e.g., employees, because the SMS message 210 must be sent individually for each employee, using point-to-point, 15 unless the sending subscriber, e.g., a company, does not object to the SMS message 210 being sent to every subscriber in the broadcasted cell 208, not just the intended recipients.
It is, therefore, an object of the present invention to allow a SMS message to be received by a particular group of subscribers.